package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import lombok.var;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.util.Collections;
import java.util.concurrent.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT ;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }
    private final BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);
    private static final ExecutorService SECKILL_ORDER_EXECUTOR=Executors.newSingleThreadExecutor();
    @PostConstruct
    public void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }
    private class VoucherOrderHandler implements Runnable {

        @Override
        public void run() {
            while (true) {
                try {
                    //1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                }
            }
        }
    }

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.尝试获取锁
        Long userId = voucherOrder.getUserId();
        var lock = redissonClient.getLock("lock:order:" + userId);
        boolean islock = lock.tryLock();
        //2.判断是否获取锁成功
        if (!islock) {
            //获取失败
            log.error("不允许重复下单");
            return;
        }
        try {
            proxy.getResult(voucherOrder);
        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            //3.释放锁
            lock.unlock();
        }

    }
    private  IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        //查询优惠卷
        //判断秒杀时间是否开始
        //判断秒杀是否结束
        //如果没有开始返回错误信息
        //如果开始，判断库存是否充足
        //如果充足扣减库存
        // 生成订单信息
        //返回订单id
        var userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString());
        //2.判断结果是否为0
        //2.2 为非0，代表没有购买资格
        if (result.intValue() != 0) {
            return Result.fail(result == 1 ? "库存不足" : "不能重复下单");
        }
        //2.1 为0，下单成功
        long orderId = redisIdWorker.nextId("order");
        VoucherOrder voucherOrder = new VoucherOrder();
        voucherOrder.setId(orderId);
        voucherOrder.setUserId(userId);
        voucherOrder.setVoucherId(voucherId);
        orderTasks.add(voucherOrder);
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        return Result.ok(orderId);
    }
//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        var voucher = seckillVoucherService.getById(voucherId);
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            return Result.fail("秒杀尚未开始");
//        }
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已经结束");
//        }
//        if (voucher.getStock() < 1) {
//            return Result.fail("库存不足");
//        }
//        Long userId = UserHolder.getUser().getId();
//        var lock = redissonClient.getLock("lock:order:" + userId);
//        boolean islock = lock.tryLock();
//        if (!islock) {
//            return Result.fail("请勿重复下单");
//        }
////        synchronized (userId.toString().intern()){
////            IVoucherOrderService proxy =(IVoucherOrderService) AopContext.currentProxy();
////            return proxy.getResult(voucherId);
////        }
//        try {
//            IVoucherOrderService proxy =(IVoucherOrderService) AopContext.currentProxy();
//            return proxy.getResult(voucherId);
//        } catch (IllegalStateException e) {
//            throw new RuntimeException(e);
//        } finally {
//            lock.unlock();
//        }
//    }

    @Override
    @Transactional(rollbackFor = Exception.class)
    public void getResult(VoucherOrder voucherOrder) {

        Long userId = voucherOrder.getUserId();
        Long voucherId = voucherOrder.getVoucherId();
        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        if (count > 0) {
            log.error("用户已经购买过一次");
            return;
        }
        var success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherId)
                .gt("stock",0)
                .update();
        if (!success) {
            log.error("库存不足");
            return ;
        }
        save(voucherOrder);
    }
}
